POWER SHOWER PUMP GUIDE

What Is Negative Head in relation to Power Shower pumps?

A Negative Head Situation exists where the pumped outlet is in a position level or above the level of the cold water storage tank. Since conventional water pumps require some gravity flow to activate the pump switching mechanisms, where there is a negative head situation they cannot start and will require some form of external switching to initiate pump start up. This can be achieved in a variety of ways as explained in The Techflow Products Solutions section below.

You will note from the diagram below which shows a typical automatic switching installation (AS) that the pump still has to be installed in a positive head position in order to ensure that the inlets of the pump are flooded.

There are other situations that can exist where conventional water pumps cannot start without external assistance. These situations occur where the outlet devices, taps, mixers, valves, etc. are too restrictive to allow sufficient gravity flow to lift the float switches. In these circumstances a Negative Head System is required.

When fitting a Techflow Negative Head System dedicated hot and cold supplies are required using the appropriate anti-aeration flange and 22mm inlet pipe work.

The Techflow Products Solutions
All SINGLE and TWIN Pumps are available with one of the following switching systems:

'NH' (Automatic Switching Negative Head)

This is a fully automated switching system which senses pressure drop when a tap, shower valve, etc. is opened. Each pump is supplied complete with a sensing unit which is fitted to the pump outlet and offers the following features:

o ** Unique system ensuring that both hot and cold outlets can be operated independently using a single switching unit.
o ** Integral by-pass system to protect pump when one side runs against a closed outlet.
o Suitable for whole house pumping applications.
o Compact pre-wired system.
** Applicable to twin ended Pumps only.

'MSA' (Manual Switching - Air Switch)

The Pump is supplied with a flush mounted push-button air switch which is operated once the shower valve or tap is opened to 'kick-start' the pump. The system includes the following features:

o Pump stops once shower valve is closed without further need to operate air-switch
o Flush mounted push-button switch available in chrome or gold finish
o Intrinsically safe switching in bathroom environment without need for a power supply
o Pump supplied complete with 5 metres of air-line pre-assembled
o Optional 5 metre extension kit available providing 10 metre operating range

'MSP' (Manual Switching - Pull Cord)

The Pump is operated from a ceiling mounted pull-cord switch which is used to 'kick-start' the pump once the shower valve or tap is opened. The following features are included:

o Pump stops once shower valve is closed without further need to operate switch
o Minimum disruption to bathroom environment and no requirement to break into tiles surfaces
o Pump pre-wired for ease of installation

For further advice on choosing the right power shower pump for your application please contact us on
0845 130 3300 or
email us at sales@pumpexpress.co.uk

_